Gluteus maximus muscle

Origin: Gluteal surface of ilium, lumbar fascia, sacrum,sacrotuberous ligament

Insertion: Gluteal tuberosity of the femur, iliotibial tract

Artery: Superior and inferior gluteal arteries

Nerve: Inferior gluteal nerve (L5, S1, S2 nerve roots)

Action: External rotation and extension of the hip joint, supports the extended knee through theiliotibial tract, chief antigravity muscle in sitting

Antagonist: Iliacus, Psoas major, Psoas minor

Description:
The Glutaeus maximus, the most superficial muscle in the gluteal region, is a broad and thick fleshy mass of a quadrilateral shape, and forms the prominence of the nates. Its large size is one of the most characteristic features of the muscular system in man, connected as it is with the power he has of maintaining the trunk in the erect posture. The muscle is remarkably coarse in structure, being made up of fasciculi lying parallel with one another and collected together into large bundles separated by fibrous septa. It arises from the posterior gluteal line of the ilium, and the rough portion of bone including the crest, immediately above and behind it; from the posterior surface of the lower part of the sacrum and the side of the coccyx; from the aponeurosis of the Sacrospinalis, the sacrotuberous ligament, and the fascia (gluteal aponeurosis) covering the Glutaeus medius. The fibers are directed obliquely downward and lateralward; those forming the upper and larger portion of the muscle, together with the superficial fibers of the lower portion, end in a thick tendinous lamina, which passes across the greater trochanter, and is inserted into the iliotibial band of the fascia lata; the deeper fibers of the lower portion of the muscle are inserted into the gluteal tuberosity between the Vastus lateralis and Adductor magnus.
Bursae—Three bursae are usually found in relation with the deep surface of this muscle. One of these, of large size, and generally multilocular, separates it from the greater trochanter; a second, often wanting, is situated on the tuberosity of the ischium; a third is found between the tendon of the muscle and that of the Vastus lateralis.